The documentation portal is undergoing maintenance. During this period, you can't create any new user credentials. If you do, you'll need to recreate the user credential after the maintenance period ends.
Effective in version 10.4.0, you can use the REST Operations Hub to launch the reverse proxy server that performs the load balancing for the Data Integration Service API requests across nodes in a Data Integration Service grid.
The REST Operations Hub is grid enabled.
For information about the reverse proxy server, see the "System Services" chapter in the Informatica 10.4.0 Application Service Guide.